The present invention relates to an apparatus and method for storing gas samples. In another aspect, the present invention relates to an apparatus and method for storing samples of soil gas.
Anomalies in the concentration of the various components of soil gas may be indicative of nearby hydrocarbon deposits, geothermal reservoirs, or deposits of radioactive ores. Prospecting for such energy deposits can be carried out rapidly with soil gas surveys which collect subsurface gaseous emanations generally at a depth from about 18 inches to about 36 inches below ground surface.
Anomalies in the helium concentration in the soil gas sample are frequently indicative of the presence of a nearby deposit. Unfortunately, a helium anomaly may only be about 50 to 100 parts per billion (ppb), which is only about 1% above background helium levels of about 5,238 ppb. Helium anomalies are thus difficult to detect.
One of the greatest difficulties in detecting anomalies of rare gases such as helium is in providing samples for analysis which contain the rare gas at a concentration representative of its concentration in the soil gas below ground level. Helium especially permeates most common materials of construction, and the survey site is frequently a great distance from analysis instruments of the required sensitivity. A helium container which can be used to reliably transport the soil gas sample from the field to the laboratory would be extremely desirable.